Fluid operated reciprocating hand tool



May 10, 1955 G. w. HARDY FLUID OPERATED RECIPROCATING HAND, TOOL 2 sheets sheet 1 Filed Nov. 5 1951 JNVENTOR. GQRDON W HARDY ww fl w May 10, 1955 e. w. HARDY FLUID OPERATED RECIPROCATING HAND TOOL 2 Sheets-Sheet 2 Filed Nov. 5, 1951 IN V EN TOR.

GORDON H. HARDY BY 2 m bfi AGE/VT United States Patent r 2,707,941 FLUID OPERATED RECIPROCATING HAND TOOL Gordon W. Hardy, Chula Vista, Calif.

Application November 5, 1951, Serial No. 254,963

3 Claims. (Cl. Ill- 164) 2,707,941 Patented May 10, 1955 ice Similar characters of reference refer to similar parts and portions throughout the several views of the drawings.

The frame 1 piston 2, valve bar 3, tool shoe 4, cylinder plugs 5 and 6, valve stops 7 and 8, cushion 9 and 10, d'etent stop 11, detent spring 12, spring stops 13 and 14, springs 15 and 16, air tube 17, valve guide 18, mufflefr 19 and 20, frame cover 21, handles 22 and 23, control valve 24, speed control valve 25, file 26, abrading shoe 27, and saw' 28 constitute the principal parts and portions of my fluid operated reciprocating hand tool.

The frame 1 is preferably a light weight aluminum casting or this frame may be made of any other suitable material as desired. In the lower portion of the frame '1 I have provided a hollow cylindrical bore 1a in which the piston 2 is reciprocally mounted. This piston 2 is provided with O-ring seals 2a and 2b at opposite ends used to operate a file, a hack-saw or any type of abradin tool as desired.

Third, to provide a tool of this class having a novel combination of reciprocating mechanism and corresponding valve structure which promotes rapid acceleration of the reciprocating mechanism of the tool in both reciprocal directions. 7

Fourth, to provide a tool of this class which is very light in weight in proportion to its utility.

Fifth, to provide a tool of this class which may be particularly adapted for use in body and fender work for repairing and rebuilding automobile bodies and the like.

Sixth, to provide a tool of this class which is very eflicient in its consumption of compressed air, proportional to the work done.

Seventh, to provide a tool of this class having novel means for adjusting the longitudinal stroke of the re ciprocating mechanism of the tool and:

Eighth, to provide a tool of this class which is very thereof and fixed to the reduced intermediate shank 2c are lateral arms 20? and 2e connected to the valve bar 3 and the tool shoe 4 respectively. The cylinder bore 1a is provided with opposed slots 1c and 1d in which the arms 2d and 2e are reciprocally mounted. Fixed to the tool shoe 4, is the file 26, all as shown best in Fig. l of the drawings. The tool shoe 4 is fixed to the arm "2e by means of the screw 2 while the file 26 is fixed to the shoe 4 by means of screws 26a and 26b extending through the moililt clip 260. This mount clip 260 is provided with simple and economical of construction, efficient in operation and which will not readily deteriorate or get out of order.

With these and other objects in view as will appear hereinafter my invention consists of certain novel features of construction, combination and arrangement of parts and portions as will be hereinafter described in detail and particularly set forth in the appended claims, reference being had to the accompanying drawings and to the characters of reference thereon forming a part of this application in which:

Figure 1 is a longitudinal vertical sectional view of my fluid operated reciprocating hand tool, showing parts and portions in elevation to facilitate the illustration.

Figure 2 is a transverse sectional view taken from the U-shdped portions at opposite ends which extend into the slots 4a and 4b in the tool shoe 4. These slots-4a and 4b'ar'e arranged in opposed relationship to each other and extend toward opposite ends of said tool shoe 4. It will be noted that the tool shoe 4 is under cut at each end on the lower side so that the slots 4a and 4b tel-mi nate at their open ends a short distance from each end of the tool shoe 4. Opposite edges of the tool shoe 4 are retained between guide tracks 1e of the frame 1 which provides for rectilinear guidance of the tool shoe 4 as the piston 2 actuates the same. The plugs 5 and 6 provide closures for the ends of the cylinder bore 1a. The valve bar 3 fixed to the arm 2d reciprocates in bore portions If and 1g of the frame 1 near opposite ends thereof The air tube 17 is fixed in the frame 1 above the valve bar 3 and receives air from the shutoff valve 24 through the passage lit and this air tube 17 delivers air to the bore portions 1] and 1g through the orifices 1i and 1k, respectively. Thevalve bar 3 is provided with annular grooves 3a and 3b which are adapted to index fit with the orifices 1 and 1k and also the orifices 1m and la, respectively, which communicate with opposite ends of the bore 1a in which the piston 2 is reciprocally mounted, all as shown best in Fig. 1 of the drawings. Fixed at the outer open end of the bore 1 is the downwardly line 2-2 of Fig. 1 showing the handle structure frag- I mentarily.

Figure 3 is an enlarged fragmentary sectional view taken from the line 33 of Fig. 1.

Figure 4 is an enlarged sectional View of the valve bar and one of the spring stops taken from the line 4==4 of Fig". l. 3

Figure 5 is a fragmentary side elevational view of my fluid operated reciprocating hand tool showing means for operating a saw in connection therewith.

Figure 6 is an end view of oneof the saw shown in Fig. 5.

Figure 7 is an end view of the other saw fixture shown in Fig. 5.

Figure 8 is a fragmentary side elevational view'of my fluid operated reciprocating hand tool showing an abrading pad in connection therewith.

fixtures p,

directed muffler 19 and fixed at the outer open end of the bore 1g isthe downwardly directed muffier 20. These muflie'rs 19 and 20 are arranged to mufiie the exhaust passing outwardlyof the bores 11 and 1g as indicated by the arrow A in Fig. 1 of the drawings. Fixed on the valve bar 3 are the valve stops 7 and 8 adapted to engage the cushions 9 and 10 respectively. These valve stops 7 and 8 are spaced on the valve bare to accomplish" indexing of the annular grooves 3a and-3b of the valve Bar 3 with the orifices 1j and 1m and 1k and In respectively. It will be noted that opposite ends of the valve bar 3 are provided with shelf portions 30 and 3d which permit b'yfpass of the orifices 1n and lm for exhaust of air from the cylinder 1a during stroking of the pistons 2. These shelves 3c and 3d provide for the closure of the orificeslj and 1k during exhaust through either of the orifices 1m or In. Thus the'spacing of the valve stops 7 and' from the cushions 9 and 10 substantially equals the" distance between the annular groove portions 311' and 3b and the inner ends of the shelves 3c and 3d, resp'ec-' tively. The detent stop 11 is fixed to the valve bar 3 and it engages the spring detent 12. This spring detent 12 is vertically resilient permitting the detent stop 11 to depress the'same and slide thereover. The detent spacing of the detent stop 11 is substantially equal to the distance between the annular groove 3a and the inner end of the shelf 3c which also corresponds with the spacing between the annular groove 3b and the inner ends of the shelf 3d. The spring stops 13 and 14 are fixed on the valve bar 3 and are arranged to be engaged by the springs 15 and 16 respectively for resiliently reciprocating the valve bar 3 in accordance with pressure exerted by the arm 2d of the piston 2 on either of the springs 15 or 16. These springs 15 and 16 are freely mounted on the valve bar 3 while the valve guide 18 is fixed thereto and engages opposite sides of the air tube 17 in order to prevent rotation of the valve bar 3 and consequent displacement of the semicircular in cross-section shelf portion 3c which are adapted to cover the ports 1 and 1k when the valve bar 3 is in either position for exhausting air from the ports 1m or In. The valve 25 is a seat control valve adapted to control the fiow of air through the ports 1h. The control valve 24 is a reciprocal valve for turning on or shutting off the air supply to the passage 1h. The cover 21 is removably mounted on the frame 1 and covers the reciprocating valve mechanism hereinbefore described. The handles 22 and 23 provide for manual control of the entire tool so that both hands of the operator may be employed for guiding or steadying the tool during its varied operation. As shown in Fig. of the drawings, I have provided a saw 28 which is composed of a conventional hack saw blade and for the purpose of mounting this hack saw blade 28 on the tool shoe 4 I have provided brackets 28a and 28b having lip portions 280 and 28d respectively engageable with the slots 4b and 4a respectively of the tool shoe 4. The brackets 28a and 28b are secure in engagement with the slotted portions 4a and 4b by means of the screws 28s and 28f which are screw threaded into the tool shoe 4. It will be noted that the brackets 28a and 28b are substantially conventional and are adapted to hold the blade 28 alternatively in two ditferent positions at right angles to each other which positioning may be accommodated by the engaging pins 28g and 28h on the bracket 28a, which pins are adapted'to engage the conventional hack saw blade opening. The abrading shoe 27 is secured to the tool shoe 4 and it is adapted to support a sheet of sand paper 27a on its lower surface and when such abrading operations are performed, the spring stops 13 and 14 are adjusted into close proximity with the springs and 16 causing very short stroke of the piston 2 and resultant high frequency motion thereof simulating high frequency vibration which is ideal for sanding operations. Attention is called to Fig. 4 of the drawing wherein the stop 14 is fixed to the valve rod 3 by meansof a set screw 14a. The valve stops 7 and 8 are secured to the valve bar by similar set screws while the detent stop 11 and the.valve guide 18 are also fixed to the valve bar 3 by screws similar to the set screws 14a. The operation of my fiuid operatedreciprocating hand tool is substantially as follows: i

When air is conducted into the internally screw threaded fitting 22a of the handle 22 and when the valve 24 is in.the open position as shownin Fig. '3 of the drawings compressed air travels downwardly through 'the speed control valve 25 and into the passage 111 from which it passes into the air tube 17 which communicates with the passages 1j and 1k with which the grooves and 3b of the valve bar 3 index. In the position as shown in Fig. 1 of the drawings compressed air is conducted through the passage 1k into annular groove 3b of the valve bar 3 and the passage 1n into the bore 1a of the frame 1 adjacent the plug 6. The compressed air forces the piston 2 toward the orifice 1m and when the piston 2 approaches the orifice 1m in close proximity thereto the spring 15 engages the spring stop 13. The spring compresses progressively until it overcomes the tension of the detent spring 12 at which time it very rapidly moves the valve bar 3 toward the mufiler 19 causing the valve stop 7 to engage the cushion 9 which indexes the groove 31: with the orifices 1i and 1m. In this position the piston 2 is very close to the orifice 1m and compressed air entering the orifice 1m reacts against the plug 5 and starts the pistons 2 moving in the opposite direction. It will be noted that when the valve bar 3 travels in the direction toward the muffier 19 and the stop 7 is against the cushion 9 that the shelf 3d at its inner end is past the orifice thus permitting the piston to exhaust air underneath the shelf and outwardly under the muffier 20. Thus each reciprocal movement of the piston 2 in the cylinder bore 1a is cushioned by the inlet of compressed air which starts it rapidly moving in the opposite direction due to the open exhaust at the opposite end of the cylinder. The detent spring 12 causes the valve bar 3 to remain stationary until one of the springs 15 or 16 is sufiiciently compressed to cause very rapid shifting of the valve bar 3 so that it opens one of the orifices 1111 or In and closes the other. Thus the reciprocating action of the tool is very rapid and very smooth and highly eflicient. It is very quiet due to the cushioned effect of the piston operation which is caused by the inlet of compressed air at each end of the stroke before the piston reaches the end of the cylinder.

The spring stops 13 and 14 may be adjusted to closer proximity to the springs 15 and 16 in order to control the length of the stroke and the frequency of the stroke of the piston 2 and the tool shoe 4 with which various tools may be connected. If it is desired to use the abrading shoe 27 as hereinbefore described the stroke is shortened and frequency is increased by adjustment of the spring stops 13 and 14 so that a high frequency vibration effect may be attained. In the operation of the file 26 or the saw 28 a long smooth stroke is desirable and the speed thereof may be regulated by the speed control valve 25 which regulates the How of compressed air into the air tube 17. The on and off switch 24 is conveniently located at the handle 22 for starting and stopping the operation of my fluid operated reciprocating hand tool.

Though I have shown and described a particular construction combination and arrangement of parts and portions, I do not wish to be limited to this particular combination construction and arrangement but desire to include in the scope of my invention the construction combination and arrangement substantially as set forth in the appended claims.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. In a tool of the class described, a frame, a cylinder on said frame, a piston reciprocally mounted in said cylinder and having arm portions extending from a position intermediate the ends and laterally of the axis of the piston, a tool shoe connected to one of said arm portions, a valve connected to the other of said arm portions, whereby movement of said piston longitudinally of said cylinder causes said valve to open an exhaust port at one end of said cylinder and index said valve with an air pressure inlet orifice at the other end of said cylinder, said 'valve consisting of a reciprocating rod mounted in said frame and having air conductor passages adjacent each opposite end of said cylinder, detent means adapted to detain said valve in each opposite position, stop means on said valve, and springs engaging said other of said arms and engageable with said stop means for reciprocating said valve member against the action of said detent means and rapidly changing the position of said valve during each reciprocal movement of said piston.

' 2. In a tool of the class described, a frame, a cylinder connected thereto, a piston reciprocally mounted in said cylinder, slots intermediate opposite ends of said cylinder in the side Walls thereof, arms connected to said piston intermediate its end and extending radially outwardly through said slot, a tool shoe secured to one of said arms, a reciprocating valve engaged by the other of said arms adapted to control the inlet and exhaust of compressed air at opposite ends of said cylinder, said valve being reciprocated by the last mentioned arm, springs engaging opposite sides of said arm and mounted on said valve, stops on said valve and engageabie by said springs, passages in said valve near each opposite end thereof, and passages in said cylinder near each opposite end thereof adapted to index with the passages in said valve, whereby reciprocal movement of said piston causes said springs to engage said stops and alternately open and close the ports in opposite ends of said cylinder for permitting successive intake and exhaust of compressed air therethrough.

3. In a tool of the class described, a frame, a cylinder, connected thereto, a piston reciprocally mounted in said cylinder, slots intermediate opposite ends of said cylinder in the side walls thereof, arms connected to said piston intermediate its end and extending radially outwardly through said slot, a tool shoe secured to one of said arms, a reciprocating valve engaged by the other of said arms adapted to control the inlet and exhaust of compressed air at opposite ends of said cylinder, said valve being reciprocated by said other of said arms, springs engaging opposite sides of said last mentioned arm and mounted on said valve, stops on said valve and engageable by said springs, passages in said valve near each opposite end thereof, passages in said cylinder near each opposite end thereof adapted to index with the passages in said valve whereby reciprocal movement of said piston causes said springs to engage said stops and alternately open and ciose the ports in opposite ends of said cylinder for permitting successive intake and exhaust of compressed air therethrough, detent stops on said valve, detent means engageahle by said detent stops for causing compression of said springs upon each movement of said valve past said detent means, a speed control valve arranged to control the inlet of compressed air to said first mentioned valve, a shut-off valve arranged to control the flow of compressed air to said speed control valve, and said tool shoe having means at opposite ends thereof for supporting various tools in connection therewith.

References Cited in the file of this patent UNl'TED STATES PATENTS 215,026 Strater, Jr. May 6, 1879 368,648 Carpenter Aug. 23, 1887 382,168 Lechtenberg May 1, 1888 968,861 Lindstrom Aug. 30 1910 1,347,444 Christiansen July 20, 1920 2,120,300 Taylor June 14, 1938 2,234,647 Kehle Mar. 11, 1941 2,555,018 Von Seggern May 29, 1951 FOREIGN PATENTS 357,191 Germany Aug. 22, 1922 

